The present invention relates generally to pallets, and more particularly to a field bin. A field bin is generally a pallet with upstanding walls. Thus, some of these features are applicable to pallets, containers and to collapsible containers independently.
There are numerous considerations in the design of a pallet or field bin. In addition to the acquisition costs, there are several costs in using and maintaining a field bin, including the cost of shipping, periodic cleaning, and repairs.
Making the field bin collapsible can reduce shipping costs. Minimizing the height of the collapsed field bin reduces the cost of shipping the field bin when empty. Decreasing the weight of the container also decreases shipping costs.
Damage to the field bin is largely incurred from the handling of the field bin with fork trucks. The runners, columns and base have direct contact with the blades and are therefore subject to the most abuse. The walls are also likely to be damaged from the repeated collapsing and erecting of the container. Although the damage cannot be eliminated, the time and cost required to repair the field bin should be minimized.
The collapsible walls of field bins often include drop walls or doors for easier access to product in the bottom of the container. Generally, each wall includes a cutout opening upwardly from approximately a mid-height level on the wall. The drop door is hingeably connected in the cutout of the wall. In order to permit the door to be opened fully, i.e. such that it is parallel to the wall and lies adjacent the wall, double hinges that permit rotation about two offset axes have been used to connect the doors to the walls. However, the cutouts reduce the strength and stability of the walls. If the doors are open, the load supportable by the walls is significantly reduced. Opening a door on a bin on which other bins are stacked could cause the stack to fail.
In order to reduce the stacking height of empty containers, some collapsible containers provide at least the longer side walls of the containers with double hinges, i.e., hinges that permit the walls to pivot about either of two vertically spaced axes, so that one wall can lie parallel and flat upon the other when both walls are in the collapsed position. Further, the walls can be collapsed in a non-sequential order. In other words, either wall can be folded down onto the base first. However, the double hinge connecting the side walls to the base does not provide a rigid connection between the side wall and the base when the side wall is in the upright position. The double hinges permit some undesired movement of the side walls relative to the base.